Most of the precise electronic instruments and equipment rely on high quality and stable power to maintain a normal operation. An uninterruptible power operating apparatus not only ensures the reliability of the power supply source, but also offers a high quality power waveform. Consequently, the uninterruptible power operating apparatus provides the best solution which ensures the reliability of power supply and supplies high quality electric power. For example, in case that the uninterruptible power operating apparatus is applied to an elevator, the elevator works stably and continuously when the utility power is interrupted or abnormal. The uninterruptible power operating apparatus ensures the safety of people.
FIG. 1 is a schematic block diagram illustrating an uninterruptible power operating apparatus according to a prior art. As shown in FIG. 1, two ends of the uninterruptible power operating apparatus 1 are electrically connected with a load L1 and an AC power source P1, respectively. The AC power source P1 is, for example, the utility power. The uninterruptible power operating apparatus 1 provides backup power to the load L1 for maintaining the operation of the load L1 when the power outputted from the AC power source P1 is interrupted or abnormal. The load L1 is, for example, an elevator. The uninterruptible power operating apparatus 1 includes a charging circuit 11, an energy storage element such as a rechargeable battery 12, a DC/DC converting circuit 13, a DC/AC converting circuit 14, a triple ends switch element 15 and a driving circuit 16. When the AC power source P1 outputs power normally, the charging circuit 11 converts the electric energy outputted from the AC power source P1 to the backup electric energy to be stored in the rechargeable battery 12. When the power outputted from the AC power source P1 is interrupted or abnormal, the backup electric energy stored in the rechargeable battery 12 is discharged and been converted by the DC/DC converting circuit 13 and the DC/AC converting circuit 14 in sequence. Consequently, an AC electric energy is converted and outputted by the DC/AC converting circuit 14. The triple ends switch element 15 is used to switch the paths according to the power supplying status of the AC power source P1. When the AC power source P1 outputs power normally, the triple ends switch element 15 is switched to be electrically connected between the AC power source P1 and the driving circuit 16 directly. When the power outputted from the AC power source P1 is interrupted or abnormal, the triple ends switch element 15 is switched to be electrically connected between the DC/AC converting circuit 14 and the driving circuit 16. Namely, according to the power supplying status of the AC power source P1, the driving circuit 16 selectively receives the electric energy outputted from the AC power source P1 or the AC electric energy outputted from the DC/AC converting circuit 14 through the triple ends switch element 15 so as to drive a motor L11 within the load L1.
However, when the power outputted from the AC power source P1 is interrupted or abnormal, the driving circuit 16 of the uninterruptible power operating apparatus 1 receives the AC electric energy outputted from the DC/AC converting circuit 14 by switching the triple ends switch element 15. At this stage, time delay occurs during the switching operation of the triple ends switch element 15, which results in that the driving circuit 16 fails to receive the AC electric energy outputted from the DC/AC converting circuit 14 by switching the triple ends switch element 15 immediately when the power outputted from the AC power source P1 is interrupted or abnormal. Under this circumstance, the driving circuit 16 drives the motor L11 within the load L1 by using the residual power energy. Therefore, the motor L11 within the load L1 decreases the efficiency or interrupts the operation at the moment when the power outputted from the AC power source P1 is interrupted or abnormal. Moreover, the backup electric energy stored in the rechargeable battery 12 of the uninterruptible power operating apparatus 1 is discharged and processed by the DC/DC converting circuit 13, the DC/AC converting circuit 14 and the driving circuit 16, and then provided to the motor L11 of the load L1. Hence, the operations of the three stage circuit including the DC/DC converting circuit 13, the DC/AC converting circuit 14 and the driving circuit 16 may cause energy loss during power conversion of the backup electric energy.
FIG. 2 is a schematic block diagram illustrating an uninterruptible power operating apparatus according to another prior art. As shown in FIG. 2, two ends of the uninterruptible power operating apparatus 2 are electrically connected with a load L2 and an AC power source P2, respectively. The AC power source P2 is, for example, the utility power. The uninterruptible power operating apparatus 2 provides backup power to the load L2 for maintaining the operation of the load L2 when the power outputted from the AC power source P2 is interrupted or abnormal. The load L2 is, for example, an elevator. The uninterruptible power operating apparatus 2 includes a charging circuit 21, an energy storage element such as a rechargeable battery 22, a DC/DC converting circuit 23, a DC/AC converting circuit 24, a first switch element 251, a second switch element 252, a triple ends switch element 253 and a driving circuit 26. When the AC power source P2 outputs power normally, the charging circuit 21 converts the electric energy outputted from the AC power source P2 to the backup electric energy to be stored in the rechargeable battery 22. When the power outputted from the AC power source P2 is interrupted or abnormal, the backup electric energy stored in the rechargeable battery 22 is discharged and converted by the DC/DC converting circuit 23 and the DC/AC converting circuit 24. Consequently, an AC electric energy is converted and outputted by the DC/AC converting circuit 24. The first switch element 251 and the second switch element 252 are turned on or turned off according to the power supplying status of the AC power source P2. When the AC power source P2 outputs power normally, the first switch element 251 is turned on to be electrically connected between the AC power source P2 and the driving circuit 26, and the second switch element 252 is turned off. Under this circumstance, the driving circuit 26 receives the electric energy outputted from the AC power source P2 through the first switch element 251 to drive the motor L21 within the load L2 directly. When the power outputted from the AC power source P2 is interrupted or abnormal, the second switch element 252 is turned on to be electrically connected between the rechargeable battery 22 and the driving circuit 26, and the first switch element 251 is turned off. Meanwhile, the backup electric energy stored in the rechargeable battery 22 is discharged and provided to the driving circuit 26. The voltage of the rechargeable battery 22 is relative low, so that the driving circuit 26 fails to operate or to work effectively by utilizing the low voltage backup electric energy discharged from the rechargeable battery 22. Hence, the driving circuit 26 needs to install an EPS (emergency power supply) port electrically connected with the DC/AC converting circuit 24. The EPS port receives the AC electric energy outputted by the DC/AC converting circuit 24 to drive the driving circuit 26, so that the driving circuit 26 receives and converts the backup electric energy discharged from the rechargeable battery 22 through the second switch element 252 to drive the motor L21 within the load L2. The triple ends switch element 253 includes a triple ends switch and is used to switch the paths according to the power supplying status of the AC power source P2. When the AC power source P2 outputs power normally, the triple ends switch element 253 is switched to be electrically connected between the AC power source P2 and the load L2 through the first switch element 251 turned on. When the power outputted from the AC power source P2 is interrupted or abnormal, the triple ends switch element 253 is switched to be electrically connected between the DC/AC converting circuit 24 and the load L2.
From above descriptions, the driving circuit 26 of the uninterruptible power operating apparatus 2 needs to employ the EPS port additionally. Hence, the uninterruptible power operating apparatus 2 costs higher. Moreover, because the voltage of the rechargeable battery 22 is relative low, the current conveyed through the wire, which is used to transfer the backup electric energy discharged from the rechargeable battery 22 to the driving circuit 26, is relative high. Hence, thicker wires are need, and the uninterruptible power operating apparatus 2 costs higher.
Therefore, there is a need of providing an uninterruptible power operating apparatus to obviate the drawbacks encountered from the prior arts.